PoE Midspan Injectors

Microsemi (formerly PowerDsine) manufacture a range of Power over Ethernet (PoE) midspan injector devices with various port densities. These devices allow power to be injected into Ethernet circuits close to the end-device that actually consumes the power.

Each unit has a network connection that is used to communicate with the SNMP agent and webserver. The power is injected via separate ports that are not instrumented for traffic monitoring.

The use of these midspan power injectors avoids the need for installing PoE hardware modules into the access layer Ethernet switches.

ENA PoE implementation

Midspan injector devices are IP addressable and have an SNMP agent that allows management access. ENA discovers and adds PoE midspan injectors to its database in a similar manner to that used for routers and Ethernet switches. PoE midspan injector devices are automatically classified as midspan injector devices and placed into their own Devices folder.

ENA PoE monitors the status of the power supply and the individual port configuration, status and power drain through the injector devices.

Each device includes an in-built webserver, which allows browser access to status and configuration settings. ENA PoE includes a user action for the context launching of a web browser.

Unlike modular Ethernet switches, ENA PoE assumes that each PoE midspan injector device is implemented as a single module.

ENA PoE injector devices

ENA PoE considers midspan injectors as devices, and as such they are placed within a subfolder of devices. Many of the midspan injector attributes are standard attributes applicable to other device types, e.g. Ports, Chassis Data and KPI tabs. This section outlines attributes of particular interest or specific to PoE management:

PoE injector attributes

Attribute

Description

Manufacturer

manufacturer name, derived by matching the manufacturer number against the first 2500 Private Enterprise Codes compiled by the Internet Assigned Numbers Authority (http://www.iana.org/assignments/enterprise-numbers). Where the manufacturer code is not matched, then the first part of the device name is taken - usually this is the manufacturer’s name. This would be Microsemi or, as it was formerly called, PowerDsine.

Model

device model.

Version

device version number.

Serial Number

device serial number.

Polled IP Address

IP address that ENA uses to poll the device.

Location

device location.

System Object Identifier

value of the system object identifier MIB for the device.

System Description

manufacturer's device description, which may include the application and boot version identifiers.

Power Budget

percentage of maximum available power when operating from a UPS.

Maximum Power

maximum power available to the device, measured in watts.

System Capabilities

traffic management capabilities of the device. It is not applicable to this device type.

Nominal Power

theoretical level of power available to the device, measured in watts.

Poll Status

indicates whether the device is currently available to poll.

PoE injector stream attributes

PoE midspan injectors supply power to network devices through their injector ports. You can monitor power supply at both the injector device and injector port level. ENA PoE can detail PoE injector device power configuration.

Attribute

Description

Operational Status

operational status of the device, i.e. On, Off.

Total Power Supplied

sum of all power supplied to the device's ports.

Voltage

mains power supply received by the PoE midspan injector.

PoE injector port attributes

PoE injector ports inject power into the end device, and so are not instrumented for traffic monitoring.

Attribute

Description

Name

port name.

Maximum Power

maximum power the port can handle, measured in watts.

Device Classification

power class of the powered device (PD).

Power Priority

Priority of the port used to decide which ports continue to supply full power to their end device, when power to midspan injector is insufficient to meet all requirements. Three states area available: Critical, High and Low (default).

Port Description

Description which can be used to identify the end device, or its purpose, that this port is supplying with power.

PoE injector port stream attributes

PoE injector ports inject power into the end device and so are not instrumented for traffic monitoring. ENA PoE can detail the status of their power delivery, updating these values using a one hour polling cycle. This information is available for graphing through the Attribute Grapher, for reporting on through Flex Reports.